Method for extracting molded product from injection molding die

ABSTRACT

A method and apparatus for extracting a molded product wherein the molded product, specifically, a shutter molded of a synthetic resin with a very small thickness, from an injection molding die at a high speed without malfunction or deformation of the molded product. The apparatus includes as essential components an opposing pair of chucking members for supplementarily supporting a molded product in the clamped state while restrictively locating it at a predetermined position, and a suction pad located in alignment with the predetermined position of the molded product for grasping the latter by the action of suction. In an alternate embodiment, two chuck arms having respective suction pads at their ends are moved into contact with the shutter from opposite sides. With the invention the molded product can completely be extracted from an injection molding die in cooperation of the chucking members with the suction pad.

This is a divisional of application No. 07/974,208 filed Nov. 10, 1992,now U.S. Pat. No. 5,417,914.

BACKGROUND OF THE INVENTION

The present invention relates generally to a method and apparatus forextracting a molded product from an injection molding die. Moreparticularly, the present invention relates to a method and apparatusfor extracting from an injection molding die a slidable shutter adaptedto be attached to a cartridge case in which a disc-shaped recordingmedium is received.

In recent years, disc-shaped recording media such as magnetic discs,optical discs, photomagnetic discs and the like have been increasinglyused owing to their advantageous properties, e.g., simple and easyhandling and large data storage capacity per unit volume of disc.

A 3.5 inch micro floppy disc as shown in FIG. 5 is a typical example ofa disc cartridge employable as a disc-shaped recording medium. Thismicro-floppy disc 1 is constructed such that a magnetic disc 5 isrotatably received in the hollow space defined between upper and lowerrectangular shell halves 2 and 3 injection-molded ofacrylonitrile-butadiene-styrene copolymer resin or the like. Themagnetic disc 5 is prepared in the form of a magnetic recording mediumhaving a magnetic layer uniformly formed on the surface of a circularhigh-molecular film base, and a ring-shaped center plate 4 is secured toa circular opening formed at the central part of the magnetic disc 5. Inaddition, a circular opening 7 is formed at the central part of thelower shell half 3 of the micro-floppy disc 1 so as to allow a motorshaft to be inserted into a substantially square motor shaft insert hole6 formed at the central part of the center plate 4.

Additionally, magnetic head insertion openings 8 are formed on the upperand lower shell halves 2 and 3 so as to allow a magnetic head and a headpad to be received in the foregoing openings 8 in order toelectromagnetically write data to or read data from the magnetic disc 5.

To prevent dust or similar foreign material from entering themicro-floppy disc 1 via the magnetic head insertion openings 8 and thenadhering to the disc, the micro-floppy disc 1 is provided with aslide-type shutter 9 for opening and closing the magnetic head insertopenings 8.

The shutter 9 has hitherto been made by bending a metal sheet such as astainless steel sheet or the like to obtain a U-shaped cross-sectionalcontour.

The shutter 9 can slidably be displaced in the direction ofopening/closing of the magnetic head insert openings 8 with the aid ofprojections extending inward of the inner wall of the shutter 9 in thevicinity of the bottom of the latter and a guide groove adapted toreceive the projections. The guide groove extends parallel to the sideedge on the front surface of the lower shell half 3. In other words, theshutter 9 can slidably be displaced within a slidable movement region 11along the side wall surfaces of the micro-floppy disc 1, which regionincludes the periphery of each magnetic head insertion opening 8.

In addition, openings 10 are formed on the shutter 9 positionallyaligned with the magnetic head insertion openings 8 so as to allow themagnetic disc 5 to be exposed to the outside therethrough when themicro-floppy disc 1 is in the operative state. On the other hand, themagnetic head insertion openings 8 are closed by the shutter 9, causingthe magnetic disc 5 to be covered with the shutter 9 as illustrated byphantom lines in FIG. 5, when the micro-floppy disc is in theinoperative (storage) state.

Recently, various proposals have been made to replace the conventionalmetal shutter with a less expensive shutter molded of a synthetic resin.See, for example, Japanese Patent Laid-Open Publications Nos. 60-231985and 64-70981. In consideration of the function of the shutter, acrystalline plastic material having a self-lubricating property, such aspolyacetal resin, has generally been used as the synthetic resin for theshutter. With a crystalline plastic material, however, it is requiredthat the molding die in which the material is injected be heated to ahigh temperature sufficient to promote growth of crystals (normallyabout 70° C. to 90° C.). As a result, the molded product must beextracted from the injection molding die also at an elevatedtemperature, typically about 80° C. to 100° C.

To extract the molded product from the mold and pass it to a subsequentproduction processing station, a chucking (extraction) apparatus asdisclosed in, e.g., Japanese Utility Model Laid-Open Publications Nos.57-4310 and 59-129517 has hitherto been used. Specifically, such achucking apparatus is constructed such that a pair of chuck members,which are opened and closed by cylinders, squeeze the molded product insuch a manner as to clamp it from opposite sides with chucking surfaces.The molded product is then extracted from the injection molding die.

However, when a shutter is molded of a synthetic resin, as alreadydiscussed, the molded product must be extracted from the injectionmolding die at a high temperature. This molded product has a very smallthickness ranging from about 0.2 mm to 0.5 mm. For this reason, when anextracting apparatus of the type described above is employed for thepurpose of extracting the molded product from the injection molding die,there arises a problem in that the molded product can be readilydeformed by only a relatively small exterior force (chucking force)imparted by the extracting apparatus. In addition, since the shutter,i.e., molded product, is deeply received in the injection molding die,when it is clamped from the opposite sides in the direction at a rightangle relative to the direction of extraction at positions offset frompredetermined positions during the extracting operation, there arisesanother problem in that an abnormally high extracting force acts on themolded product.

Further, when a U-shaped shutter 50 (molded product) having a very smallthickness is held by chucking surfaces 51 from the opposite sides in theclamped state, sometimes the shutter 50 is held in an inclined statesuch that only one side wall of the shutter 50 contacts the chuckingsurface 51, causing the rear surface 50a (U-shaped bent joint portion)of the shutter 50 to be convexly deformed, as illustrated by phantomlines in FIG. 6. Once such convex deformation occurs, precise grippingof the shutter 50 is not assured, and, moreover, correct transference ofthe shutter 50 to a subsequent processing stage can be achieved onlywith much difficulty.

Since each chucking surface 51 is generally lined with an elasticmaterial 52, left- and right-hand corner portions 50b of the rearsurface 50a forcibly encroach on both elastic materials 52, resulting insmall recesses 53 being formed thereon. The presence of these recesses53 sometimes leads to a part of the shutter 50 located directly beloweach corner portion 50b being concavely deformed.

To avoid deforming the shutter 50 by the chucking surfaces, it might beconsidered to reduce the magnitude of chucking force. However, if thechucking force is weakened, the reliability for holding the shutter 50in the clamped state is reduced. For this reason, it is very difficultto properly adjust the magnitude of the chucking force.

In another conventional extracting apparatus of the foregoing type, asuction pad is brought in close contact with the rear surface of theshutter from above so that the shutter is extracted from the injectionmolding die while maintaining the desired orientation of the shutter.However, when the apparatus is provided with a suction pad, since therear surface of the shutter has a very small thickness of about 3.6 mm,it is necessary that the position of the suction pad be preciselycontrolled in order to assure that the suction pad can provide asufficiently high suction force. For this purpose, as shown in FIG. 7,after a shutter 50 is raised a predetermined height above the injectionmolding die by actuating an ejection pin 61, the shutter 50 is broughtinto close contact with a suction pad 63 disposed at a certain deepposition in a guide 64 having inclined guide surfaces 65 formed thereonto guide the raising movement of both side surfaces of the shutter 50.

However, since the shutter 50 is still at an elevated temperature andhence is still quite soft, an abnormal force can readily be imparted tothe shutter 50 when the rear surface 50a of the shutter is inserted intothe guide 64 toward the suction pad 63 along the inclined guide surfaces65, resulting in the position of the guide 64 being largely dislocated.In an extreme case, the ejection pin 61 can be damaged or broken by theguide 64.

Japanese Utility Model Laid-Open Publication No. 57-129517 illustrates achucking apparatus constructed such that a molded product is clampedfrom opposite sides by a pair of chuck members each including a suctionpad on one side thereof. With the chucking apparatus constructed in theabove-described manner, a vacuum switch is provided to detect whether ornot the molded product is clamped by the chuck members via the suctionpads. In this case, the molded product is held by the chuck members, andeach suction pad serves merely as detecting means. Since each suctionpad is fitted into a recess formed on the chucking surface of thecorresponding chuck member, when it is used as holding means, it cannotmake soft contact with the molded product because it does not projectfrom the open end of the recess formed on the chuck member.

In case that the molded product is held merely by the suction paddisposed on one side, there is a possibility that the molded product isheld in an inclined state. In addition, in case that the molded productis held directly by the forward ends of piston rods in pneumaticcylinders, it is difficult as a practical matter to finely adjust themagnitude of holding force applied by the pneumatic cylinders. For thisreason, employment of the pneumatic cylinders in the above manner is notsuitable for holding a soft molded product such as a shutter or thelike. In addition, employment of two pneumatic cylinders for holding asingle molded product is not acceptable for economical reasons.

Further, Japanese Utility Model Laid-Open Publication No. 57-4310describes a chucking apparatus constructed such that a molded productmolded of a synthetic resin is held by a grasping member includingcontact pieces. With this construction, the grasping member, operativelyconnected to a cylinder unit, serves to grasp a molded product such asscissors by a turning movement of the grasping member about a pin.However, it is very difficult to finely adjust the magnitude of theforce for clamping the molded product with the aid of the graspingmember connected directly to the cylinder unit. Also in this case, thegrasping member grasps a member harder than the shutter. Thus, thegrasping member cannot be employed as a holding member for holding asoft molded product such as a shutter formed by a sheet material.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the foregoing,and an object thereof resides in providing a method and apparatus forextracting a molded product from an injection molding die at a highspeed without malfunction or deformation of the molded product.

To accomplish the above and other objects, the present inventionprovides a method and apparatus for extracting a molded product from aninjection molding die, wherein the apparatus includes an opposing pairof chucking members fixedly secured to a movable frame forsupplementarily holding a molded product having a U-shapedcross-sectional contour in the clamped state by bringing the chuckingmembers into contact with both side surfaces of the molded product withthe aid of elastic members attached to the forward ends of the chuckingmembers while the molded product is restrictively located at apredetermined position, and a suction pad adapted to come into airtightcontact with a rear surface of the molded product whose position hasbeen restrictively determined by the chucking members, the suction padbeing elastically displaceable at a right angle relative to thedirection of actuation of the chucking members, wherein, after themolded product has been partially removed from the injection moldingdie, it is held by the chucking members in the clamped state at apredetermined position, and, thereafter, the suction pad comes intotight contact with the rear surface of the molded product, allowing themolded product to be completely extracted from the injection molding dieas the support frame is displaced in the upward direction.

To further accomplish the above object, the present invention provides amethod and apparatus for extracting a molded product from an injectionmolding die, wherein a displaceable support frame includes an opposingpair of chuck arms adapted to linearly move toward the molded product,and suction pads projecting from the chuck arms are attached to thechuck arms such that they are located opposite to each other. When thesuction pads are elastically brought in close contact with both the sidesurfaces of the molded product, the latter is firmly held by the chuckarms in the clamped state via the suction pads, and thereafter, as themolded product is displaced in the upward direction, the molded productis extracted from the injection molding die.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a shutter for which an extractingapparatus of the present invention is employable, particularlyillustrating the structure of the shutter;

FIG. 2 is a partially sectioned front view of a first embodiment of anextracting apparatus of the invention;

FIG. 3 is a fragmentary sectional view which schematically illustratesthe structure of a second embodiment of an extracting apparatus of theinvention;

FIG. 4 is an enlarged fragmentary sectional view of the extractingapparatus shown in FIG. 3, particularly illustrating the detailedinterior structure of the apparatus;

FIG. 5 is an illustrative view of a 3.5 inch micro-floppy disc with theshutter shown in FIG. 1 attached thereto, particularly illustrating theoverall structure of the micro-floppy disc;

FIG. 6 is a fragmentary sectional view of a conventional extractingapparatus, particularly illustrating the state in which a shutter isheld in the inclined state by an opposing pair of side chucks; and

FIG. 7 is a schematic sectional view of the conventional taking-outapparatus, particularly illustrating the state in which the rear surfaceof the shutter is raised by the action of a vacuum generated by a vacuumpump.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail hereinafter withreference to the accompanying drawings which illustrate preferredembodiments of the present invention.

FIG. 1 is a perspective view of a shutter 20 employable for a 3.5 inchmicro-floppy disc (not shown) which is to be extracted from an injectionmolding die by operating an apparatus of the present invention.

The shutter 20, which has an inverted U-shape in cross-section, isinjection-molded of polyacetal resin. The shutter 20 includes inwardextending projections (not shown) at predetermined positions on theinner wall surfaces which are slidably engaged with a cartridge shell.Openings 21 are formed through the cartridge 20. When a cartridge is inuse, the openings 21 of the shutter 20 are positionally aligned with amagnetic head insert opening so that a magnetic disc received in thecartridge is exposed to the outside through the openings 21.

FIG. 2 is a partially sectioned front view of an apparatus 40 forextracting a molded product constructed in accordance with a firstembodiment of the present invention.

As shown in the drawing, the apparatus 40 includes a support frame 30having an inverted U-shape. When an upper die half (not shown) is movedaway from a lower molding die half 70 as illustrated by phantom lines inthe drawing (i.e., when the movable die half is moved away from thestationary die half), the apparatus 40 can enter the hollow spacedefined by the support frame 30 (i.e., the apparatus 40 can move in thevertical direction or in the horizontal direction as seen in thedrawing). In other words, the apparatus 40 can be displaced in theperpendicular direction relative to a parting plane 71 (i.e., not onlyin the direction marked by an arrow C, but also in the direction markedby the arrow D). when the support frame 30 is lowered, the apparatus 40is located at a position spaced away from the lower molding die half 70by a predetermined distance.

The support frame 30 includes an opposing pair of side arms 31 to whichchucking members 33 are secured. In addition, the support frame 30includes an upper arm 32 to which a suction unit including suction pad41 is secured.

A pair of chucking members 33 are secured to the side arms 31 such thatthey are located opposite to each other. Each chucking member 33 iscomposed of a pneumatic cylinder 35 having an expansible/contractiblerod 34 and a plate-shaped chucking piece 36. As a pair of chuckingpieces 36 are displaced toward each other (i.e., in the directionindicated by an arrow B in the drawing), they are very gently broughtinto contact with the shutter 20 from opposite sides thereof tosupplementarily hold the same in the clamped state.

For this purpose, a piece of sponge rubber is adhesively attached to acontact surface of each chucking piece 36 to serve as an elastic member,and the minimum distance between the opposing pair of chucking pieces 36at the time the latter come into close contact with the shutter 20 ismade to be smaller than the thickness of the shutter 20 by 0.2 mm to 0.8mm. It should be added that each chucking piece 36 is adapted to comeinto contact with a region 22 exclusive of the openings 21 formedthrough the shutter 20 as shown in FIG. 1. A soft silicone-based rubberhaving a hardness of 15 degrees or less while exhibiting excellent heatresistance is used for the sponge rubber 37.

The suction unit operates such that the suction pad 41 is downwardlydisplaced toward the shutter 20 by a predetermined distance to come intocontact with the rear surface of the shutter 20 (i.e., the upper surfaceof the inverted U-shaped shutter 20), and the foregoing displacement ofthe suction pad 41 is achieved by allowing the whole apparatus 40 to bedisplaced to the side of the lower molding die half 70. It should benoted that the position of the shutter 20 as seen in the horizontaldirection in the drawing is previously restrictively determined.

The suction unit will be described in more detail below. A tube 42communicated with a vacuum pump (not shown) is connected to the rearside of the suction pad 41 such that it extends in the interior of thesupport frame 30 through a base portion 43 fixedly secured to the upperarm 32 of the support frame 30, allowing the suction pad 41 to belocated at a predetermined position. A compression spring 44 is arrangedbetween the suction pad 41 and the base portion 43 while the tube 42extends through the coil spring 44. The compression spring 44effectively absorbs the shock caused when the suction pad 41 comes intocontact with the rear surface of the shutter 20 after it is lowered apredetermined distance. When the vacuum pump is driven in the reversedirection, air can be blown from the suction pad 41, which serves as ablowing nozzle at this time.

Alternatively, a suitable driving system may be installed on the baseportion 43 so as to allow only the suction pad 41 to be displaced inresponse to a predetermined signal transmitted from the foregoingdriving system.

The present invention has been described above with respect to anextraction apparatus which is intended to hold a single shutter in theclamped state as shown in FIG. 2. Alternatively, the present inventionmay equally be applied to an extraction apparatus for which an injectionmolding die for simultaneously molding four or eight shutters isemployed. In this case, the apparatus is constructed in a mannercorresponding to the number of shutters to be molded.

With the apparatus 40 constructed in the above-described manner, after ashutter 20 is molded in the injection molding die, the upper die half isopened and moved away from the lower die half 70. Subsequently, thesupport frame 30 is displaced to the position directly above the lowerdie half 70.

When the shutter 20 is partially removed from the lower die half 70 byactuating an ejection pin 61, both pneumatic cylinders 35 are actuatedso as to allow the chucking pieces 36 to be displaced (in the directionB) until the chucking pieces 36 are brought into soft contact with bothside surfaces of the shutter 20 via the sponge rubbers 37. Thus, theshutter 20 is restrictively located at a predetermined position while itis supplementarily supported by both chucking pieces 36 in the clampedstate from opposite sides thereof.

Next, the apparatus 40 is displaced in the D direction, causing thesuction pad 41 to come into airtight contact with the rear surface ofthe shutter 20. In contrast with the illustrated case, if the apparatus40 is constructed such that only the suction pad 41 can be displaced,the suction pad 41 is lowered a predetermined distance at the same thechucking pieces 36 come into contact with the shutter 20 from bothsides, until it is brought into contact with the rear surface of theshutter 20.

While the suction pad 41 is lowered, air is blown from the suction pad41 so that the rear surface of the shutter 20 is cooled until thesuction pad 41 comes into contact with the rear surface of the shutter20. Consequently, the shutter 20 is hardened. The vacuum pump is drivendirectly before the suction pad 41 contacts the shutter 20, whereby theinterior of tube 42 is evacuated, causing the suction pad 41 to comeinto airtight contact with the rear surface of the shutter 20.Consequently, the shutter 20 is firmly grasped by the suction pad 41,and, thereafter, as the support frame 30 is displaced away from thelower die half 71 (in the C direction), the shutter 20 is completelyremoved from the lower die half 71. Subsequently, the apparatus 40 isdisplaced in the horizontal direction so that the shutter can betransferred to a subsequent processing stage. Upon completion of thetransference of the apparatus 40 to the next step, the chucking pieces36 and the suction pad 41 are actuated in the opposite direction,whereby the shutter 20 is released from the clamped state.

According to the above embodiment of the present invention, an opposingpair of chucking members 33 are brought into soft contact with theshutter 20 from both sides thereof, and the distance between theopposing chucking pieces 36 at the time when they contact the shutter 20from the opposite sides via the sponge rubbers 37 is made smaller thanthe thickness of the shutter 20 by about 0.2 mm to 0.8 mm, whereby theshutter 20 is restrictively located at the predetermined positionwithout danger of malfunction or damage to the side surface of theshutter 20 while the latter is supplementarily supported by the chuckingpieces 36. In addition, by bringing the suction pad 41 into airtightcontact with the rear surface of the shutter 20, the latter is reliablygrasped by the chucking pieces 36 in cooperation with the suction pad 41while it is located precisely at the predetermined position.

Since soft silicone-based rubber having an excellent heat resistance isused for the sponge rubbers 37, a shutter which is still at an elevatedtemperature and readily deformable immediately after theinjection-molding operation can be handled without damage to the spongerubbers 37. In addition, since the chucking pieces 36 contact theshutter in a region 22 exclusive of openings 21, the extent of adverseinfluence can be minimized even if the shutter 20 is undesirablydeformed for an unavoidable reason.

As is apparent from the above description, according to the presentinvention, the inventive extracting apparatus is constructed such that amolded product is supplementarily held in the clamped state by anopposing pair of chucking members, and thereafter it is grasped by thesuction pad adapted to come into airtight contact with the rear surfaceof the molded product. Since the molded product is restrictively locatedat a predetermined position by bringing the chucking members into softcontact with the molded product from opposite sides, the molded productis not damaged by the chucking members. Subsequently, the molded productis grasped in a precise manner by the suction pad while it isrestrictively located at the predetermined position. In other words, theinventive extracting apparatus is constructed such that the moldedproduct is extracted from the injection molding die in cooperation ofthe chucking members with the suction pad. Thus, in contrast with theconventional apparatus constructed such that chucking members and asuction pad are separately actuated, there is no danger of deformationof the molded product. In addition, according to the present invention,since the inventive apparatus is constructed such that the suction padis brought into airtight contact with the molded product while thelatter is restrictively located at the predetermined position, themolded product can exactly be grasped without failure.

A second embodiment of an extracting device of the present inventionwill now be described in detail hereinafter with reference to FIGS. 3and 4 of the accompanying drawings.

FIG. 3 is a schematic sectional view of the extracting apparatus of thesecond embodiment, particularly illustrating the overall structure ofthe apparatus, and FIG. 4 is an enlarged sectional view of theapparatus, particularly illustrating the detailed structure of essentialcomponents constituting the apparatus, which is generally designated byreference numeral 130.

Referring to FIG. 4, a chuck driving unit 119 includes an opposing pairof chuck arms 112 and 113 on the opposite sides in the lower regionextending downward therefrom. Both the chuck arms 112 and 113 arehorizontally freely displaceable in the leftward/rightward direction. Asuction pad 118 is disposed at a position in the vicinity of thelowermost end of each of the chuck arms 112 and 113 such that the twosuction pads 118 are located opposite to each other. Each of the suctionpads 118 is pneumatically connected to a vacuum pump (not shown) whichis arranged in the chuck driving unit 119 or installed outside of thesame.

As is best seen in FIG. 4, a center core 109 is arranged inside of theshutter 120, and an ejection pin 114 extends through the center core 109in such a manner that the shutter 120 can be displaced in the upwarddirection with the aid of the ejection pin 114. Slide cores 121 and 122adapted to be slidably displaced in the leftward/rightward directionwhile the gap defined by the shutter 120 is present are arranged on theopposite sides of the center core 120.

The shutter 120 is molded of a synthetic resin by injecting a moltensynthetic resin through a nozzle (not shown) into the hollow spacedefined by the center core 109, the slide cores 121 and 122 and amovable die half 123 (to be described in more detail later).

It should be noted that the movable die half 123 is displaced away fromthe stationarydie half (i.e., in direction indicated by an arrow C inFIG. 4) upon the completion of each injection-molding operation for ashutter 120, whereby a space large enough to enable the extractingapparatus 130 to enter therein is formed.

The detailed structure of the extracting apparatus 130 will be describedbelow with reference to FIG. 4.

The extracting apparatus 130 is formed with suitable grooves (not shown)on a lower end surface 119a of the chuck driving unit 119 including arectangular support frame 119b. In addition, the extracting apparatus130 includes two slidable base portions 138 adapted to slidably movealong the aforementioned grooves in such a manner as to grasp the framelower end surface 119a from both the inside and outside surfaces of theframe lower end surface 119a. The chuck arms 112 and 113 having thesuction pads 118 attached thereto extend downward of the slidable baseportion 138.

Each of the suction pads 118 is molded of an elastomeric material suchas rubber or the like and projects inward of the chuck arms 112 and 113.This makes it possible for the suction pads 118 to be freely deformed,resulting in the forward end of each suction pad 118 being softlybrought into close contact with the shutter 120.

It should be noted that the distance between the forward end surfaces ofthe suction pads 118 at the time when the latter come into close contactwith the shutter 120 is made smaller than the thickness of the shutter120 by 0.2 to 1.0 mm. As long as the foregoing dimensional differenceremains within the range of 0.2 to 1.0 mm, it is assured that theforward end surface of each suction pad 118 is very softly deformed.When the shutter 120 is extracted from the injection-molding die uponcompletion of each injection molding operation, cooling air or anothercooling fluid is ejected from the suction pads 118 toward the shutter120, causing at least a part of the shutter 120 having the cooling airor the cooling fluid in contact therewith to be effectively cooled,resulting in the mechanical strength of the part being substantiallyincreased.

Next, a mechanism for displacing the chuck arms 112 and 113 will bedescribed below.

Flexible wires 136 are joined to the slidable base portion 138 such thatthey are connected to the lowermost end of a piston rod 141 adapted toslidably move in a pneumatic cylinder 140. On the other hand, a pair ofcompression springs 135 are disposed on the opposite side relative tothe flexible wires 136 with the frame lower end surface 119a locatedtherebetween so as to normally bias the slidable base portions 138 awayfrom each other. In the case illustrated, two compression springs 135are provided. It should of course be understood that the presentinvention may equally be applied to a single compression spring disposedwith a central partition wall removed from the frame lower end surface119a.

As shown in FIG. 4, a tube 137, by way of which each suction pad 118 ispneumatically connected to the vacuum pump, (not shown) is arranged suchthat it extends from the bottom of each suction pad 118 through eachchuck arm, each slidable base portion 138 and the frame upper endportion until it reaches the vacuum pump. Of course, a part of the tube137 between the slidable base portion 138 and the frame upper endportion is in the form of a flexible tube so as to accommodate theslidable movement of each slidable base portion 138.

Next, injection-molding of the shutter 120 and the operation of theextracting apparatus 130 will be described in detail below.

While a gap corresponding to the shutter 120 is formed in the closedinjection molding die, molten synthetic resin is injected into the gapthrough a nozzle (not shown) to injection-mold the shutter 120 of thesynthetic resin.

Subsequently, the movable die half 123 is raised in the direction C inFIG. 4, and thereafter both of the slide cores 121 and 122 are displacedaway from each other to some extent. In addition, the ejection pin 114in the center core 109 is raised so as to raise the shutter 120 abovethe upper surface of the slide cores 121 and 122, and thereafter theextracting apparatus 130 is displaced until the suction pads 118 arelocated opposite to the upper side surfaces of the shutter 120 which hasbeen raised.

It is recommended that the extracting apparatus 130 be previouslydisplaced to a predetermined position before the shutter 120 is raisedby the ejection pin 114.

On completion of the displacement of the extracting apparatus 130 to thepredetermined position, a cooling fluid such as air or the like is blownfrom both suction pads 118, whereby the shutter 120 is cooled to atemperature at which the shutter 120 can no longer be readily deformed.Then, the pneumatic cylinder 140 is actuated to pull the flexible wires136, causing the chuck arms 112 and 113 to approach respective sidesurfaces of the shutter 120. At the same time or just before the suctionpads 118 contact the shutter 120, the vacuum pump is driven to evacuatethe region in the vicinity of the injection molding die so as to allowboth suction pads 118 to firmly hold the shutter 120 by the action ofthe vacuum produced by the vacuum pump via the suction pads 118.

The position two which the suction pad 120 are displaced canrestrictively be determined by bringing a part of the slidable baseportion 138 into contact with a stopper 134 disposed on the supportframe 119b at a predetermined position. Fine positional adjustment foreach suction pad 118 can be precisely achieved by adjustably changingthe contact position of the stopper 134 or by employing a mechanism (notshown) for dislocating the stopper 134.

After the shutter 20 is firmly held by both suction pads 118, theextracting apparatus 130 is displaced in the direction so as to extractthe shutter 120 (i.e., in the D direction in FIG. 4) until the shutter120 is completely drawn out of the injection molding die. Subsequently,the shutter 120 is transferred to the next stage.

The present invention has been described above with respect to anembodiment wherein a single molded product (shutter) is produced.Alternatively, the present invention may be applied to an embodimentwherein an injection molding die for simultaneously molding four oreight shutters is firmly held by both the chuck arms 112 and 113. Insuch a case, the flexible wires 136, the pulleys 133 and the pneumaticcylinder 140 as mentioned above can unchangeably be used in the sameform described above.

As is apparent from the above description, according to the presentinvention, an opposing pair of chuck arms are slidably displaced towardeach other below the support frame, and, on completion of eachinjection-molding operation for a molded product, i.e., a shutter, theyare displaced together with the shutter in the upward direction. Inaddition, the positions where the chuck arms contact the shutter can beprecisely adjusted without undesirable deformation of the shutter.Further, suction pads, each molded of an elastomeric material, arearranged inside the chuck arms such that the flexibility of each suctionpad can satisfactorily be utilized. Consequently, a sufficiently highholding force can be maintained in spite of the fact that a smallexterior force is imparted to the shutter, with the result that ashutter molded of a synthetic resin with a small thickness and at a hightemperature can quickly be extracted from the injection molding diewithout malfunction or deformation of the shutter. Especially in casethe chuck arms are positionally offset relative to the injection moldingdie, this positional offset can be compensated by the flexibility ofeach suction pad. In other words, the magnitude of an exterior forceimparted to the shutter can be made small.

What is claimed is:
 1. A method for extracting a U-shaped molded productfrom an injection molding die, comprising the steps of:moving adisplaceable support frame over said injection molding die; moving ahorizontally opposing pair of chuck arms mounted on said displaceablesupport frame toward said molded product so as to bring suction pads,respectively projecting toward said molded product from said chuck arms,elastically into close contact with respective side surfaces of saidmolded product: activating a vacuum pump connected to said suction pads:evacuating a region proximate to said suction pads. said regionincluding said molded product: gripping said respective side surfaceswith said suction pads with a predetermined force in accordance with avacuum produced by said vacuum pump; and displacing said support framein an upward direction to extract said molded product from saidinjection molding die.
 2. The method of claim 1, wherein said step ofmoving said horizontally opposing pair of chuck arms toward said moldedproduct comprises actuating a pneumatic cylinder to pull a pair ofsupport wires attached to slidable base portions slidably mounted onsaid support frame and carrying said chuck arms thereon.
 3. The methodof claim 1, further comprising, prior to said step of moving saidhorizontally opposing pair of chuck arms toward said molded product, thestep of blowing air through said suction pads to cool said moldedproduct.
 4. The method of claim 1, wherein said step of moving saidhorizontally opposing pair of chuck arms including providing a minimumdistance between said chuck arms, when said chuck arms are in contactwith said molded product, which is smaller than a thickness of saidmolded product by 0.2 to 1.0 mm.